Electromagnetic radiation is a known mechanism for delivering energy to an object. The ability of electromagnetic radiation to penetrate and heat an object in a rapid and effective manner has proven advantageous in many chemical and industrial processes. In the past, radio frequency (RF) energy has been used to heat articles by, for example, induction heating or dielectric heating. However, the use of RF energy to heat articles can have some drawbacks. For example, the wavelength of RF energy can make it difficult to transmit and launch RF energy in an efficient manner. The present invention involves discoveries for minimizing and/or eliminating many of the drawbacks conventionally associated with the use of RF energy to heat articles.